Alginate has been used for many years as a gelling agent in puddings, fruit fillings, dessert gels, and structured foods, as a water binder in frozen foods, pastry fillings syrups, and icings, as an emulsifier in salad dressings and meat flavor sauces, and as a stabilizer in beer, fruit juice, toppings, sauces and gravies.
It is well known that alginates react with polyvalent cations, including zinc, aluminum, copper and calcium, to form gels or precipitates. It is also well known that the viscosity of sodium alginate solutions is altered by the addition of monovalent salts but that such salts do not induce gelation.
We have surprisingly found that alginate solutions do, in fact, form diffusion-set gels upon addition to certain kinds of water, such as seawater, having high concentrations of sodium ions.